This is exactly what I've said I know how to do :)
More clear: I want the included picture to redirect to a page, not to another picture, therefore redirecting the page that includes it... if possible, 'cause I haven't found it in any tutorial so far

sorry, out of brain space,
redirect to a html page instead of an image ??
not sure it can be done either
it should be cause you can make <img src='filename'php'> for generated images
how about a html file with a breakout script that loads your page